Atopodentatus Gets Our Attention

The Unique Atopodentatus unicus

As the new for 2019 PNSO figures arrive at Everything Dinosaur, we have time to reflect on one of the new models. The replica of the bizarre Triassic marine reptile Atopodentatus (A. unicus). Although Atopodentatus was named and scientifically described less than five years ago, this three-metre-long Tetrapod has certainly attracted a great deal of debate. Where it sits phylogenetically has yet to be resolved. Tentatively, it could be placed within the Sauropterygia. The Sauropterygia is an extremely diverse Superorder of reptiles. It includes the placodonts, plesiosaurs, nothosaurs and the Pachypleurosauria.*

The New for 2019 PNSO Atopodentatus Model

The new for 2019 PNSO Atopodentatus model.

Picture Credit: Everything Dinosaur

Pachypleurosauria* – PNSO have also introduced a pachypleurosaur into their “Prehistoric Animal Toys That Accompany Your Growth” range, one of the twenty-four new models is “Ricky” the Keichousaurus.

At First it was a Filter Feeder

The fossil material associated with this genus comes from south-western China (Guanling Formation). The strata are thought to be Middle Triassic in age (Anisian faunal stage) and these marine deposits have helped scientists to construct a picture of how life bounced back from the devastating End Permian extinction event. When first described, Atopodentatus was thought to feed by stirring up mud on the seabed to filter out small invertebrates. The rostrum was thought to be downturned, resulting in this reptile having a vertical, zipper-like jaw.

A Life Reconstruction of Atopodentatus unicus (2014)

Strange Triassic marine reptile. Atopodentatus unicus was thought to have had a downturned rostrum, a unique jaw configuration not found in other vertebrates.

Turns out, Atopodentatus did not have such a unique and highly specialised feeding adaptation after all, but it is nonetheless, quite remarkable. Additional specimens led to a new interpretation of the shape of the skull and rather than having a downturned rostrum, Atopodentatus had a set of jaws shaped like a hammerhead. It was proposed that Atopodentatus was herbivorous. The teeth lining the hammerhead were used to scrape seaweed and algae from rocks. The plant material was then sucked into the back of the mouth and filtered by the long, thin tooth mesh.

To read Everything Dinosaur’s 2016 article about the reinterpretation of Atopodentatus: Atopodentatus Unzipped

Atopodentatus unicus still had a highly specialised feeding adaptation, although one not quite a peculiar as previously thought. It still represents the oldest record of herbivory within marine reptiles and its discovery has helped scientists to better understand how marine ecosystems recovered after the End Permian extinction event.

Remarking on the addition of an Atopodentatus to the PNSO model range, a spokesperson from Everything Dinosaur commented:

“As a Chinese company, PNSO have attempted to focus on prehistoric animals that lived in China. This has resulted in a whole new and never before created set of prehistoric animal replicas such as Atopodentatus and Keichousaurus. Thanks to PNSO, Everything Dinosaur customers now have an even greater variety of prehistoric animal models to collect.”